The present invention relates to orbital launch systems in general, and more particularly to manned orbital systems which incorporate a manned orbital stage.
Launch vehicles, while continuing to improve in reliability, nevertheless have rates of failure which are a concern if they are used to transport people into space. As with high performance jet aircraft, which are also subject to rates of failure which would be considered high for military or commercial transport, the overall safety of a spacecraft which carries passengers is considerably enhanced if it is provided with a system for separating the passenger carrying portion of the vehicle from the other stage or stages of the launch vehicle. The Mercury and Apollo capsules, as well as Russian manned spacecraft have used a solid rocket motors which can pull the capsule away from the launch vehicle during the early portion of the boost phase. To reduce the performance penalty of carrying these solid rockets abort motors, they are jettisoned as soon as they are no longer needed.
The Gemini-B spacecraft which was to be used for the USAF Manned Orbital Laboratory Program incorporated both ejection seats and six solid rocket retrofire motors which served double duty as abort rockets for separating the Gemini from the Titan 3M in the event of launch vehicle failure. Moreover, if not used for abort, the same solid rocket motors could be used to deorbit the Gemini-B spacecraft. Other manned launch vehicle designs such as an early design for the Shuttle Orbiter proposed firing an escape rocket system after it was no longer needed for an abort to add velocity to the manned orbital stage. In still other proposed manned vehicle concepts, engines used during the boost phase can also be used as abort engines.
Since the announcement of the shuttle retirement in 2010, a clear need has been identified for a manned orbital vehicle which can be developed before the shuttle retirement date. Such a rapidly developed manned orbital system requires new concepts for integrating vehicle functions to achieve highly reliable lightweight systems with operational simplicity.